VIDEO: PM lays wreath at National War Memorial

The House of Commons is back in action, kicked off by an exhilarating show of support for the sergeant-at-arms of the House of Commons, who was among those who opened fire Wednesday on the gunman who stormed Parliament Hill.

Applause from all sides of the House rained down on a stoic Kevin Vickers as he carried the mace into the legislative chamber.

Vickers was largely expressionless, save for an occasional nod of acknowledgment. At one point, he appeared close to tears during the ovation, which lasted several minutes. Several more ovations ensued over the course of the morning.

Prime Minister Stephen Harper delivered a statement to express the government’s gratitude for the work of the police and security services, and to reiterate that Canada won’t be cowed by Wednesday’s attack.

“In this struggle in which we are engaged, in which not only our finest values must be pushed to work, so must be, and will be, the highest unity and resolve,” Harper said.

“We will not be intimidated. We will be vigilant, but we will not run scared. We will be prudent, but we will not panic. Here we are, in our seats, in our chamber in the very heart of Canadian democracy, and the work is going on.”

Harper also indicated that an effort to toughen up the “surveillance, detention and arrest” powers of the Canadian Security Intelligence Service would be forthcoming in short order.

“They need to be much strengthened, and I assure you, Mr. Speaker, that work — which is already underway — will be expedited.”

Harper’s remarks ended with the remarkable spectacle of the prime minister walking across the floor to embrace and shake hands with both Liberal Leader Justin Trudeau and NDP Leader Tom Mulcair.

Earlier in the morning, heavy hearts and high security were on full display at the National War Memorial as Harper arrived to pay tribute to the Canadian soldier killed in the shooting.

Harper was on hand to lay flowers at the cenotaph where Cpl. Nathan Cirillo was fatally shot by a gunman who then stormed Parliament Hill before dying in a hail of gunfire that echoed through the marble-lined halls of the Centre Block.

As Harper arrived, officers swooped in to detain a man who police later said tried to breach the crime scene — a reference to the memorial itself, where Cirillo was serving as an honour guard at the time of the shooting.

“Get down on the ground,” yelled one officer as several police, guns drawn and trained on the dishevelled-looking man, approached and placed him in handcuffs without incident.

None of the commotion seemed to disrupt the solemnity at the memorial, where Harper and wife Laureen quietly laid a bouquet of flowers, paused briefly, their heads bowed, before turning to leave.

Several other MPs were on hand to pay their respects. An impromptu singing of O Canada even rippled through the crowd at one point.

At the same time, however, politicians, police forces and intelligence officials were beginning to undertake the long work of assessing security around Parliament Hill — and the safety of the country itself — in the wake of the shocking attacks in the nation’s capital.

The Parliament Buildings remained under close surveillance early today as the RCMP continued to sweep the area for evidence.

They are still piecing together the events that led to the fatal shooting of Cirillo and the burst of bullets that echoed later inside Parliament’s Hall of Honour.

Michael Zehaf Bibeau, born in 1982 and known to police in Montreal and Vancouver, has been identified as the gunman. He was killed just feet from where hundreds of MPs were meeting for their weekly caucus meetings.

Three other people injured in the melee were released from hospital Wednesday, including one person with a minor gunshot wound.

The shootings placed the heart of the national capital under lockdown throughout the day as police scoured the city’s downtown core for other possible assailants. By Thursday morning, however, Ottawa police said they believed only one gunman was involved in the attacks.

Const. Marc Soucy said no other assailants were being sought, but added the investigation was ongoing.

Parliament Hill remains closed to visitors, however, and a full investigation into House of Commons security is underway.

As late as 9:30 at night — almost 12 hours after the first shots were fired — some MPs were still being evacuated after a long lockdown, and one government source said Bibeau’s body was still lying in the hallway.

Early Thursday morning, a government statement said Ottawa police and the RCMP had lifted the downtown Ottawa safety perimeter and that federal public servants could now return to their offices.

Police say they do not yet know Bibeau’s motive, but Harper has already drawn a link between his brazen actions and international terrorism. In a televised address late Wednesday, he said Canada would never be intimidated.

What exactly a redoubling of efforts means will be addressed in the coming days.

Already, Canada has sent six fighter jets, surveillance and airlift assistance and 600 Canadian Forces personnel to fight the Islamic State of Iraq and the Levant (ISIL). In the last few weeks, there has also been heightened political scrutiny around Canada’s ability to watch and apprehend radicalized Canadians who many have gone overseas and later returned.

But whether Bibeau is somehow linked to ISIL, or can be considered a radicalized Canadian, has not yet been established.

So many questions swirl around the attacks: How did Bibeau manage to get through the front doors of Parliament’s Centre Block, and will security need to be permanently adjusted? Is he connected to any larger group that wishes Canada ill? Could someone have stopped Bibeau before he acted?

The fact that Bibeau struck only days after two Canadian soldiers in St-Jean-sur-Richelieu, Que. were hit by a car has only heightened the anxiety around the incident. The slain assailant, Martin Couture Rouleau, has been described as a radicalized Muslim.

Gen. Tom Lawson, the chief of the defence staff, issued a statement late Wednesday saying they are assessing the “current security environment and evaluating the need for additional security measures at Canadian Armed Forces installations…”

A fresh political debate is no doubt in the offing, but in the short-term the federal leaders were focused on condemning Bibeau’s actions and rallying Canadians together.

Already, there was a sense expressed by some that something had been irrevocably changed — as it had after a man hijacked a bus 25 years ago and drove it on to the lawn of Parliament Hill, and after the Sept. 11 terror attacks in the United States.

Members of the public are required to use a specific entrance on Parliament Hill where there is a security screening area, but Bibeau apparently forced his way through the doors MPs, ministers, staff members and reporters are permitted to use.

“I think the intention was to try to make Parliament not look like Fort Knox,” said Liberal MP Marc Garneau. “But we’ve crossed a river today.”